Free Collisions in a Microgravity Many-Particle Experiment. II.The Collision Dynamics of Dust-Coated Chondrules
Free Collisions in a Microgravity Many-Particle Experiment. II.The Collision Dynamics of Dust-Coated Chondrules
复制标题
微重力多粒子实验中的自由碰撞。
DOI：
10.1016/j.icarus.2011.11.036
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发表时间：
2012
期刊：
影响因子：
3.2
通讯作者：
J.
中科院分区：
文献类型：
--
作者：
Beitz;E.;Guttler;C.;Weidling;R.;Blum;J.
早期太阳系中的行星体的形成很难理解，尤其是毫米以上的尘埃聚集体的增长最近在我们的理解中被证明是一个困难的任务(Zsom，A.，Ormel，C.W.，Güttler，C.，Blum，J.，Dullemond，C.P.[2010]。阿斯特龙。占星术，513，A57)。实验室实验表明，这种大小的尘埃聚集体只有在不合理的低速度下才能相互粘连。然而，在原行星盘中，毫米大小的粒子已经被认为是无处不在的。人们可以找到固体球粒陨石形式的遗迹，作为球粒陨石的主要成分。大多数球粒陨石被发现具有一个细粒的边缘，据推测它是由太阳星云中聚集的尘埃颗粒形成的。为了研究这些被尘埃覆盖的球粒陨石对球粒陨石和可能的行星体形成的影响，我们在几个厘米−1的速度下进行了毫米大小的尘埃包裹的球粒相似物之间的碰撞实验。对于直径2毫米和3毫米的被体积填充因子为0.18和0.35-0.58的尘埃边缘覆盖的球粒陨石类似物，我们发现了几个厘米−1的粘贴速度，这个速度高于相同大小的尘埃聚集体的粘贴速度。因此，我们得出结论，球粒可能是深入理解较大天体碰撞生长的重要一步。此外，我们还分析了尘埃聚集体和非包覆球粒类似物中的碰撞行为。虽然尘埃聚集体和固体球粒相似物都没有显示出它们物种之间的碰撞粘在一起，但我们发现这两个组分之间的碰撞具有更高的碰撞效率，这让我们猜测，球粒可能是年轻太阳系中较大天体生长的“催化剂”。
The formation of planetesimals in the early Solar System is hardly understood, and in particular the growth of dust aggregates above millimeter sizes has recently turned out to be a difficult task in our understanding (Zsom, A., Ormel, C.W., Güttler, C., Blum, J., Dullemond, C.P. [2010]. Astron. Astrophys., 513, A57). Laboratory experiments have shown that dust aggregates of these sizes stick to one another only at unreasonably low velocities. However, in the protoplanetary disk, millimeter-sized particles are known to have been ubiquitous. One can find relics of them in the form of solid chondrules as the main constituent of chondrites. Most of these chondrules were found to feature a fine-grained rim, which is hypothesized to have formed from accreting dust grains in the solar nebula. To study the influence of these dust-coated chondrules on the formation of chondrites and possibly planetesimals, we conducted collision experiments between millimeter-sized, dust-coated chondrule analogs at velocities of a few cms−1. For 2 and 3mm diameter chondrule analogs covered by dusty rims of a volume filling factor of 0.18 and 0.35–0.58, we found sticking velocities of a few cms−1. This velocity is higher than the sticking velocity of dust aggregates of the same size. We therefore conclude that chondrules may be an important step towards a deeper understanding of the collisional growth of larger bodies. Moreover, we analyzed the collision behavior in an ensemble of dust aggregates and non-coated chondrule analogs. While neither the dust aggregates nor the solid chondrule analogs show sticking in collisions among their species, we found an enhanced sicking efficiency in collisions between the two constituents, which leads us to the conjecture that chondrules might act as “catalyzers” for the growth of larger bodies in the young Solar System.